The invention concerns a valve with a through-going axial bore, a first spindle axially displaceable in the bore, an elastic/flexible seal placed at the one end surface of the first spindle, at least two hollow connection branches each of which connects the valve to an outer coupling, said first spindle in a first position forming a first annular sealing surface between the outer surface of the seal and the inner bottom of the valve body, which contains the outlet opening. The invention also concerns a method of closing a valve.
From EP 468,957 a valve is known for the taking of samples, e.g. within the foodstuffs industry, where the bottling of milk, fruit juices and the like is carried out, and where there is a need for an aseptically-sealing valve for the taking of the samples. Such an aseptic seal is also suitable within, for example, the pharmaceutical industry. The above-mentioned patent publication discloses such a valve which can be used for this purpose, but where between the spindle lying in the valve housing and the bottom of the valve housing, a seating is formed solely by closing against the container from which the sample is to be removed. There hereby arises a risk that a contamination of the seating occurs, whereby bacteria can be transferred in connection with the actual taking of the sample, whereby the result of the sample-taking is not correct.
It is thus desirable to provide a valve whereby it is possible to carry out the sample-taking without any risk of contamination occurring at the place at which the sample is taken, and thus that the samples taken are not incorrect.
This object is achieved with a valve of the kind disclosed in the preamble, and also where the first spindle lies coaxially inside a second axially displaceable and hollow spindle lying in the bore, the end surface of which or parts thereof form a second annular sealing surface between the outer surface of the seal and the inner bottom of the valve body at a second position radially from the first annular sealing surface.
The manner in which the valve functions is thus that a double sealing is achieved between the spindles and the bottom, so that the outermost annular seating can be disinfected by steam being blown in through one of the connection stubs when this outermost seating is not activated and when the first seating is activated, i.e. when the inner spindle is at the bottom. This position will typically be held for a period of a minute, during which the disinfection takes place. Hereafter, the outer seating will be activated by the outer spindle moving to the bottom, whereby an annular sealing surface is formed around the annular sealing surface of the first seating.
Hereafter, the inner spindle can be drawn back, whereby the inner seating is inactivated, after which a sample can be taken by the drawing back of the outer seating, in that the bacterial flora which is now on the inner seating originates exclusively from the container in which the valve is mounted, which means that the sampling which takes place will reflect the correct condition, and in that the outer seating, as explained above, has been sterilised by means of the steam.
The spindles can be activated mechanically, but can also be activated by means of compressed air, where the controlling of this takes the movement pattern between the two spindles into account.
By providing a valve according to the invention and as further disclosed in claim 2 and 3, an expedient manner is achieved in which to bring about the movement pattern between the first and second spindle.
By providing a valve according to the invention and as further disclosed in claim 4, it is avoided that the spindles execute a rotating movement, but exclusively execute the axial movement, which is of great importance when the spindles are at the bottom during the formation of both first and second seating.
By providing a valve according to the invention and as further disclosed in claim 5 and 6, the possibility is achieved of activating the spindles mechanically.
By providing a valve according to the invention and as further disclosed in claim 7 and 8, it is achieved that the two seatings are well-defined and with a well-defined separation.
The invention also concerns a method as disclosed in claim 9 and 10, by which method it is achieved that there does not occur a transfer of bacteria between the samples which are taken.